SAN DIEGO COUNTY AIR POLLUTION CONTROL DISTRICT

RULE 69.4 - STATIONARY RECIPROCATING INTERNAL COMBUSTION ENGINES - REASONABLY AVAILABLE CONTROL TECHNOLOGY
(Adopted 9/27/94; Rev. Effective 11/15/00)

(a) APPLICABILITY

(1) Except as provided in Section (b), this rule shall apply to stationary internal combustion engines with a brake horsepower (bhp) rating of 50 or greater located at a major stationary source of oxides of nitrogen (NOx).

(2) An engine subject to this rule shall not be subject to Rule 68.

(b) EXEMPTIONS

(1) This rule shall not apply to the following:

(i) Engines used exclusively in connection with a structure designed for and used as a dwelling for not more than four families.

(ii) Engines used exclusively in agricultural operations for the growing of crops or the raising of fowl or animals.

(iii) Any engine when operated exclusively within a permitted test cell solely for the research, development, or testing of gas turbine engines or their components.

(iv) Any engine when operated exclusively within a permitted test cell solely for the research, development, or testing of reciprocating internal combustion engines or their components.

(2) The provisions of Section (d) of this rule shall not apply to the following:

(i) Any engine which operates less than 200 hours per calendar year.

(ii) Any emergency standby engine provided that operation of the engine for non-emergency purposes does not exceed 52 hours per calendar year.

(iii) Any emergency standby engine at a nuclear power generating station subject to the requirements of the Nuclear Regulatory Commission provided that operation of the engine for non-emergency purposes does not exceed 200 hours per calendar year.

(iv) Any engine used exclusively in conjunction with military tactical support equipment.

An owner or operator of an engine who is claiming an exemption pursuant to Subsection (b)(2) shall conduct annual maintenance of the engine as recommended by the engine manufacturer or as specified by any other maintenance procedure approved in writing by the Air Pollution Control Officer and shall maintain records in accordance with Subsections (e)(1) and (e)(2) of this rule.

(c) DEFINITIONS

For the purposes of this rule, the following definitions shall apply:

(1) "Add-on Control Equipment" means any technology that is used to reduce emissions from the exhaust gas stream of an engine and is installed downstream of the engine.

(2) "Brake Horsepower Rating, bhp" means the maximum continuous brake horsepower output rating as specified by the engine manufacturer and listed on the engine nameplate, if available, regardless of any derating.

(3) "Emergency Standby Engine" means an engine used exclusively in emergency situations, except as provided in Subsections (b)(2)(ii) and (b)(2)(iii), to drive an electrical generator, an air compressor or a water pump.

(4) "Emergency Situation" means any one of the following:

(i) An unforeseen electrical power failure from the serving utility or of on-site electrical transmission equipment.

(ii) An unforeseen flood or fire, or a life-threatening situation.

(iii) Operation of emergency generators for Federal Aviation Administration licensed or military airports for the purpose of providing power in anticipation of a power failure due to severe storm activity.

Emergency situation shall not include operation for purposes of supplying power for distribution to an electrical grid, operation for training purposes, or other foreseeable events.

(5) "Fossil Derived Gaseous Fuel" means gaseous fuel including, but not limited to, natural gas, methane, ethane, propane, butane, and gases stored as liquids at high pressure such as liquefied petroleum gas, but excluding waste derived gaseous fuel.

(6) "Lean-Burn Engine" means an engine that is designed to operate with an air-to-fuel ratio that is more than 1.1 times the stoichiometric air-to-fuel ratio.

(7) "Major Stationary Source of NOx" means a stationary source which emits or has the potential to emit 50 tons or more of NOx per year.

(8) "Military Tactical Support Equipment" means the same as defined in Rule 2.

(9) "Portable Emission Unit" means the same as defined in Rule 20.1.

(10) "Reasonably Available Control Technology (RACT)" means the lowest emission limit that a particular source is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility.

(11) "Rich-Burn Engine" means an engine that is designed to operate with an air-to-fuel ratio less than or equal to 1.1 times the stoichiometric air-to-fuel ratio.

(12) "Stationary Internal Combustion Engine" or "Engine" means a spark or compression ignited, reciprocating internal combustion engine which is not a portable emission unit.

(13) "Stationary Source" means the same as is defined in Rule 2.

(14) "Stoichiometric Air-to-Fuel Ratio" means the chemically balanced air-to-fuel ratio at which all fuel and all oxygen in the air and fuel mixture are theoretically consumed by combustion.

(15) "Uncontrolled NOx Emissions" means NOx emissions from an engine before application of add-on control equipment.

(16) "Waste Derived Gaseous Fuel" means gaseous fuel including, but not limited to, digester gas and landfill gas, but excluding fossil derived gaseous fuel.

(d) STANDARDS

(1) A person shall not operate a stationary internal combustion engine subject to this rule unless:

(i) Uncontrolled NOx emissions from the following engines are reduced with add-on control equipment by not less than the following:

Engine Category

Weight Percent Reduction

Rich-burn engines using fossil derived gaseous fuel or gasoline

90

Lean-burn engines using fossil derived gaseous fuel

80

Engines using exclusively waste derived gaseous fuel

80

or

(ii) The emissions of NOx, in parts per million by volume (ppmv), calculated as nitrogen dioxide at 15% oxygen on a dry basis, or in grams of NOx per brake horsepower-hour, are not greater than the following:

Engine Category

Concentration
of NOx
g/bhp-hr (ppmv)

Rich-burn engines using fossil derived gaseous fuel or gasoline

0.9 (50)

Lean-burn engines using gaseous fuel

2.3 (125)

Engines using exclusively waste derived gaseous fuel

2.3 (125)

Engines using diesel or kerosene fuel

9.0 (700)

(2) For all engines subject to Subsection (d)(1) of this rule, emissions of carbon monoxide (CO), calculated at 15% oxygen on a dry basis, shall not exceed 4500 ppmv.

(3) An owner or operator of an engine subject to this rule shall conduct annual maintenance of the engine as recommended by the engine manufacturer or as specified by any other maintenance procedure approved in writing by the Air Pollution Control Officer.

(e) MONITORING AND RECORDKEEPING REQUIREMENTS

(1) An owner or operator of an engine subject to this rule shall keep the following records and shall maintain these records on-site for at least the same period of time as the engine to which the records apply is located at the site:

(i) engine manufacturer name and model number;

(ii) brake horsepower output rating;

(iii) combustion method (i.e. rich-burn or lean-burn);

(iv) fuel type;

(v) a manual of recommended maintenance as provided by the engine manufacturer, or other maintenance procedure as approved in writing by the Air Pollution Control Officer; and

(vi) records of annual engine maintenance, including dates maintenance was performed.

(2) In addition to the records required by Subsection (e)(1), an owner or operator of an engine exempt pursuant to Subsection (b)(2) from the requirements of Section (d) shall maintain an operating log containing, at a minimum, the following:

(i) dates and times of engine operation. If applicable, indicate whether the operation was for non-emergency purposes or during an emergency situation and the nature of the emergency, if available; and

(ii) total cumulative hours of operation per calendar year, based on actual readings of the engine hour or fuel meter.

The records specified in Subsection (e)(2)(i) are not required if total engine operations for any purpose, including emergency situations, do not exceed 52 hours in a calendar year.

(3) In addition to the records required by Subsection (e)(1), an owner or operator of a rich-burn engine subject to the requirements of Section (d) shall measure and record at least once each calendar month those operating parameters determined necessary to ensure compliance by the Air Pollution Control Officer. Such operating parameters may include but are not limited to:

(i) temperature of the inlet and outlet of the control equipment;

(ii) engine air-to-fuel ratio; and

(iii) engine inlet manifold temperature and pressure.

(4) In addition to the records required by Subsection (e)(1), an owner or operator of a lean-burn engine using gaseous fuel subject to the requirements of Section (d) shall also measure and record at least once each calendar month those operating parameters determined necessary to ensure compliance by the Air Pollution Control Officer. Such operating parameters may include but are not limited to:

(i) engine air-to-fuel ratio or automatic air-to-fuel ratio control signal voltage;

(ii) engine exhaust gas temperature; and

(iii) engine inlet manifold temperature and pressure.

(5) In addition to the records required by Subsection (e)(1), an owner or operator of an engine using diesel fuel subject to the requirements of Section (d) shall also measure and record at least once each calendar month those operating parameters determined necessary to ensure compliance by the Air Pollution Control Officer. Such operating parameters may include but are not limited to:

(i) engine air-to-fuel ratio;

(ii) engine exhaust gas temperature; and

(iii) engine inlet manifold temperature and pressure.

(6) All records required by Subsections (e)(2) through (e)(5) shall be retained on-site for at least three years and made available to the District upon request.

(f) TEST METHODS

(1) To determine compliance with Section (d), measurement of NOx, CO, carbon dioxide (CO2) and oxygen content of exhaust gas shall be determined in accordance with San Diego County Air Pollution Control District Test Method 100, Air Resources Board (ARB) Test Method 100 or equivalent Environmental Protection Agency (EPA) Test Method and a source test protocol approved in writing by the Air Pollution Control Officer.

(2) The averaging period to calculate NOx and CO emission concentrations and to determine compliance shall be at least 30 minutes and not more than 60 minutes. NOx and CO emission concentrations shall be calculated as an average of three subtests.

(3) Emissions source testing, if applicable, shall be performed at no less than 80 percent of the brake horsepower rating. If an owner or operator of an engine demonstrates to the satisfaction of the Air Pollution Control Officer that the engine cannot operate at these conditions, then emissions source testing shall be performed at the highest achievable continuous brake horsepower rating or under the typical duty cycle or typical operational mode of the engine.